ASA 125th Meeting Ottawa 1993 May

5aPP9. A computer model of the physiological basis of the extraction of
pitch from tone complexes.

Ray Meddis

Michael J. Hewitt

Dept. of Human Sci., Univ. of Technol., Loughborough LE11 3TU, UK

A low pitch sensation can be heard when a mid-frequency (e.g., 500--4000
Hz) carrier is amplitude modulated at a rate between 100 and 400 Hz. The output
of multipolar neurons in the ventral cochlear nucleus are known to reflect
strongly modulation of the acoustic stimulus and even to amplify it. Other
cells in the inferior colliculus respond by increasing their rate of firing
when a rate of amplitude modulation, critical to that cell, is applied to a
stimulating tone. The system to be described consists of a model of the
auditory periphery that simulates auditory-nerve fiber input, arrays of
multipolar point-neuron models that receive this input, and arrays of inferior
colliculus unit models that receive input from the multipolar cells. Individual
model units behave similarly to physiological units. Arrays of IC model units
also show many properties associated with psychophysical studies of pitch
including the ability to extract ambiguous pitch from inharmonic tone
complexes.